apologyyoudaoicibaDictYouDict[apology 词源字典]
apology: [16] The original meaning of apology was ‘formal self-justification’, often used as the title of a piece of writing rebutting criticism (as in the Apology of Sir Thomas More, knight 1533). This is indicative of the word’s origins in Greek apologíā, a derivative of the verb apologeisthai ‘speak in one’s defence’, formed from the prefix apo- ‘away, off’ and logos ‘speech’ (source of English logic).

It entered English through either French apologie or Latin apologia (which was separately borrowed into English as a Latinism in the late 18th century). The meaning ‘expression of regret for offence given’ developed in the late 16th century.
=> logic[apology etymology, apology origin, 英语词源]
apology (n.)youdaoicibaDictYouDict
early 15c., "defense, justification," from Late Latin apologia, from Greek apologia "a speech in defense," from apologeisthai "to speak in one's defense," from apologos "an account, story," from apo- "from, off" (see apo-) + logos "speech" (see lecture (n.)).

The original English sense of "self-justification" yielded a meaning "frank expression of regret for wrong done," first recorded 1590s, but this was not the main sense until 18c. The old sense tends to emerge in Latin form apologia (first attested in English 1784), especially since J.H. Newman's "Apologia pro Vita Sua" (1864).